Name______KEY_____________________Period_________Date____________
Atoms and Static Electricity
1. Explain how there can be charge inside matter yet the matter is electrically neutral.

The charges are balanced. Neutral atoms have equal numbers of protons and
electrons.
2. Explain the difference between an electrically charged object and a neutral object.

An electrically charged object has an imbalance of protons and electrons, while
an electrically neutral object has equal numbers of protons and electrons.
3. Is an object’s net charge positive or negative if it loses electrons?

An object that has lost electrons is considered positive. It is known as an ion.
4. Why can’t an atom lose protons to become an ion?

The number of protons determines the atomic number and the identity of the
atom. Only electrons can be lost or gained to form ions.
5. What flows when there is a current in a wire?

Current in a wire is the result of the flow of free electrons through the metal.
6. What kind of force is there between like charges? Opposite charges?

Like charges have a repulsive force. Opposite charges have an attractive force.
7. Why do you feel a shock when you touch a doorknob? What causes this phenomenon?

You build up charges then touch a doorknob, those charges transfer from your
hand to the metal doorknob. This is a process of static electricity.
8. Can you feel a shock from static electricity if you touch the wooden part of a door?
Explain based on your past observations in lab.

The wooden part of a door should not produce a spark because wood is an
insulator and will not conduct electricity.
Name_____KEY_____________________Period_________Date____________
Coulomb’s Law
1. In terms of attraction and repulsion, how do negative particles affect negative particles? How
do negatives affect positives?

Negative particles repel other negative particles, but attract positive particles.
2. Consider the electric force between a pair of charged particles a certain distance apart. By
Coulomb's law:
a. If the charge on one of the particles is doubled, the force is (doubled)
b. If, instead, the charge on both particles is doubled, the force is (quadrupled)
c. If instead the distance between the particles is halved, the force is (quadrupled)
d. If the distance is halved, and the charge of both particles is doubled, the force is 16
times as great.
3. Two particles, each with a charge of 1 C, are separated by a distance of 1 meter. What is the
force between the particles?

(
)
(
)(
(
)
)
= 9 x 109 N
4. Calculate the force between a 0.05 C charge and a 0.03 C charge 2 meters apart.

(
)
(
)(
(
)
)
= 3.38 x 106 N
5. Calculate the force between a 0.05 C charge and a 0.03 C charge 4 meters apart.

(
)
(
)(
(
)
)
= 8.44 x 105 N
6. Joann has rubbed a balloon with wool to give it a charge of -1.0 x 10-6 C. She then acquires a
plastic golf tube with a charge of +4.0 x 10-6 C localized at a given position. She holds the
location of charge on the plastic golf tube a distance of 50.0 cm above the balloon. Determine
the electrical force of attraction between the golf tube and the balloon. Is it an attractive or
repulsive force?

(
)
(
)(
(
 It is an attractive force
)
)
= 0.144 N
7. Determine the electrical force of attraction between two balloons which are charged with the
opposite type of charge. The charge on both balloons is 6.0 x 10-7 C and they are separated
by a distance of 0.50 m.

(
)
(
)(
(
)
)
= 0.013 N
8. When sugar is poured from the box into the sugar bowl, the rubbing of sugar grains creates a
static electric charge that repels the grains, and causes sugar to go flying out in all directions.
If two sugar grains each acquire a charge of 3.0 x 10-11 C at a separation of 8.0 x 10-5 m, with
what force will they repel each other?

(
)
(
)(
(
)
)
= 1.01 x 10-7 N
9. The force between two charges is 2 N. The distance between the charges is 2 × 10-4 m. If one
of the charges is 3 × 10-6 C, what is the strength of the other charge?


(
(
)(
)
)(
)
= 3.0 x 10-12 C
10. How far apart are two protons if they exert a force of repulsion of 1 N? The charge on a
single proton: (qp) = +1.6x10-19 Coulomb.

(
)
(
)(
)
= 1.5 x 10-14 C
Name______KEY_____________________Period_________Date____________
Methods of Charging
1. A glass rod stroked with silk becomes positively charged because
a. the silk removes electrons from the rod
b. the rod removes electrons from the silk
c. the friction creates a positive charge
d. the silk gains protons
2. Explain how an object that is electrically neutral can be attracted to an object that is charged.
 When you bring an uncharged body near a charged body, the electrons in the
uncharged body move toward, or away from the charged body depending on the
polarity of the charge on the charged body. This causes the side of the uncharged
body closest to the charged body to have an opposite charge so they attract.
3. In the examples below, electric charge is transferred by which method?
a)
b)
Conduction
Induction / Conduction
Use the following diagram to answer questions 4 &5:
4. If you observe that the charge on balloon B is negative, what can you conclude about the
charge on balloon A?
a. It has a positive charge. or it is neutral.
b. It has a negative charge.
c. It has no charge.
d. It has a negative or neutral charge.
5. What can you conclude about the charge on balloon C?
a. It has a positive charge.
b. It has a negative charge.
c. It has no charge.
d. It has a negative or neutral charge
6. A positively charged balloon will stick to a wooden wall. It does this by polarizing molecules
in the wooden wall to create an oppositely-charged surface. Draw the appropriate diagram,
illustrating charges on both the balloon and in the wall.
7. Which of the diagrams below represents the effect of bringing a positively charged rod near
(but not touching) an electroscope.
 Diagram 3 is the answer.
8. A negatively charged balloon is brought near a neutral conducting sphere as shown below.
As it approaches, charge within the sphere will distribute itself in a very specific manner.
Which one of the diagrams below properly depicts the distribution of charge in the sphere?
 Diagram c is the answer.
9. Consider below a single metal insulated sphere, initially uncharged. The diagrams show a
charging procedure with a positive rod. Draw the correct charges in the diagrams.